The present invention relates to transmission and reception of video signals.
A digital television (TV) set receives a broadcast wave to display an image thereof. In addition, a digital TV set is generally used to receive playback video signals from an external video output device connected via various transmitting units to the digital TV set to thereby display an image of the signals. The High-Definition Multimedia Interface (HDMI; a registered trademark of HDMI Licensing, LLC) is known as an uncompressed digital interface to connect a digital TV set to an external audio-visual signal device. The HDMI includes an interface to transmit signals of the Transition Minimized Differential Signaling (TMDS) as an audio-visual signal transmission scheme and an interface of Consumer Electronics Control (CEC) to transmit device control signals. The Digital Living Network Alliance (DLNA; a registered trademark of Digital Living Network Alliance) to connect a digital TV set via an interface using Ethernet (a registered trademark of Fuji Xerox Co., Ltd.) to an external audio-visual signal device has also come into wide use.
JP-A-2009-200788 describes a technique to solve a problem in which when a digital TV set is connected via HDMI and DLNA to an external audio-visual device, it is not possible to play back contents on DLNA if the band of the network is being used by a second network device. According to the technique, there is provided a receiving device including a network interface and a digital interface to transmit audio-visual data. The receiving device includes a unit to detect an audio-visual transmitting device on a network to connect to the network interface, a unit to detect an audio-visual transmitting device on a network to connect to the digital interface, a receiving unit to receive audio-visual data from the digital interface and audio-visual data from the network interface, and a control unit to control the network interface and the digital interface. The control unit performs control such that even when the audio-visual transmitting device is connected via the network interface, if it is coupled with the digital interface, audio-visual data is received via the digital interface from the audio-visual transmitting device. When the audio-visual transmitting device is not connected to the digital interface and is coupled via the network interface, audio-visual data is received via the network interface.